Hello everyone I have a 2006 Pontiac Grand prix Special edition with the series 3 3.8L. and 137xxx Miles
Im pretty DIYer and would like to solve this problem myself.
After the car has sat overnight or 5 hours (probably just long enough to cool down.) and I start it up if I move the car or just rev the engine in park it will make a sloshing water sound, almost as if there was standing water that is being moved now. after driving for a 1/4 mile It doesnt make the noise anymore until it sits.
I checked my coolant today and the overflow jug was a little low, it was fine at the radiator, I topped it off and The noise persists. I had someone else inside the car rev it in park and I was looking at the engine bay and had them rev it, I couldnt hear the noise over the motor but they said they heard it inside.
Transmission fluid and level is good. The plastic Elbows have been replaced with metal. I thought maybe it was a leaking heater core but my passenger side floorboard is dry and I dont get a sweet smell. Would a LIM Gasket failure cause this noise only at startup? Wasnt the LIM gasket material changed in the series 3 revision and wasnt nearly as big as a problem?
Please please please any insight would be wonderful, I know that this is the best resource for this and im suprised we still have active members on this forum . Really dont want to be neglectful to my car and have a larger issue later.